The era of cheap, high grade phosphate rock in easily exploited reserves is over. Phosphate rock grades are decreasing worldwide as the richer deposits are mined out. While there is plenty of low grade phosphate rock in the world which can be recovered it is becoming more expensive to produce good grade rock for easy processing into phosphoric acid and other fertilizer products.
Before now phosphate rock has not necessarily needed flotation to produce an easily marketable grade product. This is now changing, and flotation is necessary for most rock recovery to either produce an acceptable and marketable product or to reduce the level of contaminants which prevent easy processing of phosphate rock into phosphoric acid and other fertilizer products.
For many years it has been common practice to use flotation to upgrade mined phosphate to produce marketable Phosphate Rock. Originally mechanical flotation cells were used, and in most cases the amount of phosphate lost in the flotation tailings was at a high enough level to warrant using scavenger cells, even though this was rarely done. Column Flotation improved the situation but none of the commercially available column flotation cells performed that much better than the mechanical cells.
The DEC Flotation column was developed to overcome the shortcomings of the other commercial column flotation cells and it has been proven to do a remarkable job.
The secondary recovery grade could be processed to be in the 68-74 BPL range. An additional bonus is that the hydraulic cuts can be filled with sand tailings to produce land suitable for industrial and residential use. Many phosphate deposits around the world have tailings deposits which can be treated in this way to produce high grade saleable phosphate rock
As high grade phosphate rocks are used up there is more concentration on producing saleable phosphate rock from lower grade phosphates which are often contaminated with silica and clay.
The DEC Flotation column run a number of test programs in Florida where the level of silica and metallic oxides has been reduced to a point where the phosphate rock can be easily processed to produce phosphoric acid and other fertilizers.